Iron-regulated outer membrane proteins and non-siderophore-mediated iron acquisition by Paracoccus denitrificans |
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Authors: | Sechan Wee Sharon Hardesty Murty VVS Madiraju Brian J Wilkinson |
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Institution: | Microbiology Group, Department of Biological Sciences, Illinois State University, Normal, IL, U.S.A. |
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Abstract: | Abstract Deprivation of Paracoccus denitrificans of iron in sodium molybdate-containing medium caused a slower rate of growth and lower final cell yield, in contrast to our previous studies in non-sodium molybdate-containing medium, where iron deprivation had little effect on growth rate. Five high M r outer membrane proteins and catechol production were induced in iron-deprived cultures. The fifth protein, M r 72 000, was produced later than the others. Growth of iron-deprived cells in medium containing 20 μM ferric citrate repressed siderophore and iron deprivation-induced protein production, and led to production of an M r 23 000 outer membrane protein (half maximum production after 5 h). Synthesis of the M r 23 000 and high M r proteins appeared to be mutally exclusive, and to be regulated by the cell's iron status. Cells inoculated into medium containing 20 μM ferric citrate took up 92% of the iron within 1 h, suggesting the occurrence of a nonsiderophore mediated, 'low affinity' iron uptake pathway. |
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Keywords: | Paracoccus denitrificans Iron-regulated protein Iron uptake |
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